Track Underlay

[Lee Ward]

In my previous N gauge layout, I used the preformed Woodlands Scenics foam underlay.

Having never built a 009 layout, I was wondering what thickness and width of (cork?) underlay is usual?

Cheers Lee

[Hobby]

Up to the builder, many of us don't bother with underlay at all! I have only used some on my new layout because I needed a little depth so I could run the point rodding out of sight otherwise I wouldn't bother. The only other reason I can think of is to give the ballast some "shoulder" but as that doesn't apply to many narrow gauge lines its academic... I sometimes wonder if the "requirement" for underlay is a myth put about by the makers of cork sheets!

[B.Meldon]

I tend to agree.
The noise levels are so low in 009 especialy with the newer locos iit is just not worth the bother.
Also in my opinion underlay of any type can be a complete pain making the track 'float' and increase the chances of dips and steps in the rail.
In my opinion it is far better to fix the track down onto a

[Graeme Dunbar]

I've always used either cork or the dark grey/black thin and quite firm foam used as cork replacement, but I intend to try what Brian does next time round. I think Iain Rice describes something similar and calls it "floating track base" where foam or something similar is placed between the track bed and underlying baseboard. I did try thicker camping mat foam but that was no better.

Having made one "portable" layout using MDF my preferred material is 6 mm ply -  but it drums loudly. The underlay seems to have little effect. I'm hoping that having the track glued firmly to a narrower base will impropve matters.

[Hobby]

Regarding the noise, it does help until you ballast it, then you make it all solid again and negate any benefit from the underlay. As we tend to use a sound box as a baseboard and put our layout on top of it I'd suggest that sound deadening material inside the baseboard would be more effective. TBH the noise it makes when running I rather prefer to complete silence!

[Lee Ward]

Thanks for your replies. As the layout I'm building is a test bed for a future larger layout, I'll give the cork a miss and see how it goes. I hadn't thought about the fact that NG tend to have shallower ballast compared to SG. As this is my first NG layout, it's sometimes difficult to switch over from SG thinking.

If anyone is interested, here's a link to a thread about my layout on NGRM: Lubstree Wharf

Lee

[JulienW]

Coming back to Iain Rice's methods - essentially decoupling vibrating loco mechanisms from the sound box of the layout baseboard - one of the key things was to also use a flexible glue to avoid undoing all the work of cutting and sticking the foam in place by then making it (effectively) solid with the addition of the 'traditional' PVA+water mix.

If it is sound deadening that is needed I wonder if parking the hollow baseboard with something - foam sheet, expanded polystyrene, horsehair-based car insulation? - would also do the same job as Hobby suggests.

As others have said having 2 or 3 mm of cork underlay between the bottom of the track and the hard baseboard top can be a useful space for running wier-in-tube point actuation (easier to cut a trench in the cork), and it may also even out any inconsistencies in a flat-topped baseboard (or plywood sub base if using an open-frame baseboard). It's also quite useful for making the ballast shoulder, but that may be less of an issue with those down-at-heel NG lines we tend to model (though may be more important if your line is a modern preserved one).

[B.Meldon]

Julien is correct, you can get an uneven trackbed when using plywood, but this is usually only at the joints and with careful pre planning it is possible to only have joints in the plywood trackbed in areas where the track is flat and level, thus virtually removing any problem.
In addition, a 1/4 ply trackbed is very good for the transitions between flat and graded track. It just naturally bends to give the transitions.
There is however sometimes a need to pack between the plywood and the track, we have just used sections of card at various thicknesses for this.
We also always fix the track down with track pins, but sadly Peco no longer make the shorter track pins that do not stick out through 6mm ply, they only sell the longer pins now that will go all the way through, creating sharp points on the underside of the boards.

One other tip that I have always found most useful is to pre-bend the rails into the rough shapes needed of any curves rather than just bending the flexi track and fixing it down under tension.

Brian Meldon

[Hobby]

As others have said having 2 or 3 mm of cork underlay between the bottom of the track and the hard baseboard top can be a useful space for running wire-in-tube point actuation (easier to cut a trench in the cork),

This is my latest layout (Kingdom of Ostrovia on NGRM, Lee!) showing how I've used the cork underlay.

[Graeme Dunbar]

Coming back to Iain Rice's methods - essentially decoupling vibrating loco mechanisms from the sound box of the layout baseboard - one of the key things was to also use a flexible glue to avoid undoing all the work of cutting and sticking the foam in place by then making it (effectively) solid with the addition of the 'traditional' PVA+water mix.

If it is sound deadening that is needed I wonder if parking the hollow baseboard with something - foam sheet, expanded polystyrene, horsehair-based car insulation? - would also do the same job as Hobby suggests.

I think one of Iain Rice's suggestions was to use builder's expanding spray foam in cavities under the baseboard. I'm not so sure about that one. It seems to get everywhere when I spray it, but people used it for terrain on top of the baseboard.

I feel that horsehair-like material may have merit. I've seen sheets of similar looking material for laminate flooring underlay. If laying a ply or similar floating track base over the stuff it would seem to be a vaguely similar situation to laying laminate. I presume the underlay evens out irregularities and dampens noise satisfactorily.

[Sioned Arrowsmith]

Having had the luxury of being able to experiment in place, I've tried out several options. Baseboard is 12mm ply (there's no requirement for portability, so weight isn't an issue, and it's nicely self-supporting over reasonable gaps) and I've laid different sections of track on this by:

• directly pinning
• pinning through cork
• gluing cork to base then sticking track with matt medium (effectively flexible adhesive)
• sitting loose on cork (between fixed sections)
• sitting loose directly on the base

and to be honest I'm regretting all attempts to fix the track, apart from the necessity for points operation. By far the quietest, and apparently most reliable, is the loose track on cork.

[B.Meldon]

Having had the luxury of being able to experiment in place, I've tried out several options. Baseboard is 12mm ply (there's no requirement for portability, so weight isn't an issue, and it's nicely self-supporting over reasonable gaps) and I've laid different sections of track on this by:

• directly pinning
• pinning through cork
• gluing cork to base then sticking track with matt medium (effectively flexible adhesive)
• sitting loose on cork (between fixed sections)
• sitting loose directly on the base

and to be honest I'm regretting all attempts to fix the track, apart from the necessity for points operation. By far the quietest, and apparently most reliable, is the loose track on cork.

Have you applied the ballast yet? This will make a big differance to the noise levels, and without it the track does not look right.

Did you pre-bend the rails for the curves?
Did you pre-drill the plastic sleepers for the track pins? If you do not the pins can distort the sleepers.

Having a complete flat baseboard is not just a weight issue it will give you far more noise than having a 1/4 (6mm) ply trackbed under the track only suported on a frame work. (But it needs more work and pre-planning of the track plan etc.)

Brian Meldon

[Sioned Arrowsmith]

Have you applied the ballast yet? This will make a big differance to the noise levels, and without it the track does not look right.

Not yet -- I'm having some wiring issues (and distractions from non-modelling hobbies).

Did you pre-bend the rails for the curves?
Did you pre-drill the plastic sleepers for the track pins? If you do not the pins can distort the sleepers.

Dodged it by using set track for all the curves :)

Having a complete flat baseboard is not just a weight issue it will give you far more noise than having a 1/4 (6mm) ply trackbed under the track only suported on a frame work.

This fact is completely unintuitive to me -- I had expected a stiff, heavy board to be far more resistant to picking up vibrations from a small train.

[B.Meldon]

Have you applied the ballast yet? This will make a big differance to the noise levels, and without it the track does not look right.

Not yet -- I'm having some wiring issues (and distractions from non-modelling hobbies).

Is this an electrofrog point issue?
If so if you like, just post the track diagram on here and we can help you.

Brian Meldon

[B.Meldon]

Having a complete flat baseboard is not just a weight issue it will give you far more noise than having a 1/4 (6mm) ply trackbed under the track only suported on a frame work.

This fact is completely unintuitive to me -- I had expected a stiff, heavy board to be far more resistant to picking up vibrations from a small train.

I agree it does appear to be unintuitive. But it is true.
I think what happens is that a larger bit of wood acts like a sounding board amplifying the vibrations by resonating over a large area, where as with a smaller section of wood, especialy when cut to the curves of the track and suported on a frame, the vibrations ony resonate over a small area?

But I am not an expert on the properties of sound vibrations in wood, so perhaps others can better explain why this works the way it does.

Brian Meldon